Laboratories routinely stain biological tissue specimens deposited on laboratory slides for subsequent pathologic examination to detect and/or monitor tissue abnormalities. Automated tissue staining systems allow batch staining of large numbers of slides containing tissue specimens for subsequent examination. In the course of a staining process, the tissue specimens are exposed to a series of well-defined processing steps that ultimately produces a properly stained specimen for examination. Automation of the staining process significantly reduces the time required to stain tissue specimens, reduces the incidence of human error and allows processing parameters to be altered in an efficient manner. Improvements to slide staining systems are continually sought in the interest of reliability, performance, speed and cost.